NEW YORK, Aug. 1 (Yonhap) -- A senior South Korean diplomat to the United Nations on Monday cautioned against hasty optimism over negotiations with North Korea despite the resumption of talks after years of stalemate.

The official, speaking to reporters on the condition of anonymity, said Pyongyang seems to be seeking a dialogue in a bid to achieve nuclear power status, win international recognition of an ongoing hereditary power transition and obtain investment or economic assistance.

"Fool me once, shame on you. Fool me twice, shame on me," he said, using an American saying to describe the North's past records of reneging on deals with dialogue partners.

"We have been so very disappointed and frustrated. We should not repeat that," he added.

His caution came as North Korea and the U.S. conducted two days of high-level talks in New York last week, which both sides said were "constructive."

The first formal dialogue between the two nations in 19 months followed a rare inter-Korean dialogue on denuclearization a week earlier in Bali, Indonesia, on the margins of a regional security forum.

On the North's intentions behind its recent peace gestures, the official said it is to "induce comments that recognize it as a nuclear state, or lead to interpretations as such, win recognition from many countries for a power secession, and draw investment or assistance amid economic difficulties."

He said he expects the North to use a typical tactic to draw a line between talks with the U.S. and relations with South Korea to maximize its gains.

He emphasized the need for close coordination between Seoul and Washington.

"South Korea-U.S. coordination is relatively easy in a frosty, confrontational phase (with North Korea), but once dialogue begins, coordination between South Korea and the U.S. gets more important. That is now the situation," he said.

State Department spokesman Mark Toner gave no clear answer when asked about the U.S. position on whether inter-Korean talks are needed more in the so-called second-stage denuclearization process.

South Korea and the U.S. have been pushing for a three-tiered approach -- inter-Korean dialogue, Pyongyang-Washington talks, and then the six-way nuclear talks.